This invention relates to the production of objects formed by winding a series of continuous fibers, and more particularly, to the produttion of objects formed by controlling the width of a series of continuous glass fibers impregnated with a resin prior to winding onto a rotating support.
Devices which wind a series of continuous fibers onto a rotating support are known in the art and generally comprise a storage device upon which there are provided a plurality of spools of fiber, a rotating support and a distribution head to assure orderly distribution of the fibers on the rotating support. Illustratively, the fiber may be obtained by drawing a continuous strand of molten glass by mechanical means. The device further comprises a plurality of guide elements for guiding the fibers from the various spools into an essentially planar layer of separate parallel fibers, or separate parallel groups of fibers. These guide elements may also impart a tension to the layer of fibers and direct the layer to a resin impregnation vat unless they have been impregated with this substance during a previous operation.
Depending on factors such as the shape and dimensions of the object to be formed, the distribution head can deliver a single group of fibers, formed by combining the individual fibers, or an essentially planar layer of separate parallel fibers. In this latter case, the distribution head has the structure of a comb provided with parallel teeth that maintain separation between the fibers of the layer during the entire operation of winding the fibers onto the rotating support.
This system of distribution of fibers in layer form does not pose any particular problem when the width of the layer deposited on the rotating support does not need to be varied.
However, in some instances the width of the layer must be varied periodically during the winding, as in the case when windings must be formed on an irregularly shaped mold fastened to the rotating support. In such a case it is possible to obtain variation of the width of the layer by causing the comb structure of the distribution head to rotate slightly about an axis perpendicular to the plane of the layer of fibers and therefore partially align itself with the direction of travel of the fibers.
Unfortunately, this method of rotating the distribution head has limited advantage since such rotation increases the tension of the layer by increasing the friction of the fibers on the teeth of the comb, especially the teeth at the opposite ends of the comb structure. This increase in tension can lead to breakage of fibers and adversely affect the quality of the resulting product.
Furthermore, experience shows that such rotation of the comb structure is only effective to compress a layer of width L to a layer of width 0.5L at most. Difficulties are encountered when it is desired to make objects requiring a much greater reduction of width in the layer.